Alfredsson tied the game with a shorthanded goal with 28.6 seconds remaining in regulation, and Colin Greening won it with a goal at 7:39 of the second overtime to give the Senators a 2-1 win against the Pittsburgh Penguins in Game 3 of the Eastern Conference Semifinals.

Instead of being down 3-0, the Senators trail the best-of-7 series 2-1 with Game 4 Wednesday night at Scotiabank Place (7:30 p.m. ET, NBCSN, CBC, RDS).

"I'm sure they look at it like this one hurts, they could have put a stranglehold on us," Alfredsson said. "Now we're right back in it."

When a slashing penalty was called on Senators defenseman Erik Karlsson at 18:33 of the third period, it appeared the powerhouse Penguins would coast to a commanding series lead.

But with Ottawa goaltender Craig Anderson, who finished with 49 saves in another stellar performance, on the bench for an extra attacker, the Penguins somehow left the greatest player in Senators history all alone in front of their net.

Milan Michalek saw Alfredsson cruising in front and put a wrist shot toward him, allowing the Senators' all-time leading scorer to tip the puck into the top corner past goalie Tomas Vokoun, sending the sellout crowd of 20,500 into a state of delirium moments after they thought they were witnessing what would have virtually amounted to the end of their team's season.

"When you get rewarded and score the goal you can feel the whole building the way it erupted and that gives you energy," Alfredsson said. "It's a great feeling."

The feeling wasn't quite so great for the Penguins.

"You like to think you can hold onto the puck for the final 1:27 of a power play," Pittsburgh coach Dan Bylsma said. "That wasn't the case."

After a back-and-forth period of furious hockey in the first overtime, Greening stepped to the fore in the second when Andre Benoit's sharp-angle shot forced Vokoun into a difficult save (his 46th of the night), but he couldn't get to Greening's shot on the rebound.

It was Greening's third straight game with a goal, clearly the biggest.

"I think if you look at our team, especially in the latter part of the season, we've been winning games when we've had to," Greening said with blood trickling down his cheek from a high stick he took in regulation, one that left some fiberglass in his face that had to be removed after the game.

"In a situation like tonight when you're down 1-0, to be honest, they were playing really well in the last 10 minutes, they were staying above us and it was hard to get any momentum. But we had to keep at it and stay with the structure of our team. It was nice to see because you get rewarded for things like that."

It was the second straight time these fans saw a last-minute game-tying goal from the Senators. In Game 4 of their five-game first-round series against the Montreal Canadiens, the prior time the Senators played at home, Cory Conacher scored with 22.6 seconds to play in regulation to allow Kyle Turris to win it in overtime and give Ottawa a 3-1 series lead.

"We'd rather be up 4-1 or 5-1, there's no question," Alfredsson said. "But for some reason we find ourselves in some tough spots at times. It's not always going to work out, but you've done it enough times that you believe you can do it. That's half the battle at times."

The Penguins took a 1-0 lead on a goal by Tyler Kennedy with 1:07 to go in the second period after the Senators had played nearly flawless hockey for most of it. But the first glaring mistake they made cost them dearly.

After a number of failed clearing attempts, one final one by Michalek wound up on the stick of Pittsburgh's Matt Cooke. Karlsson slid toward Cooke to block a potential centering pass, but that left Kennedy wide open in the slot. Cooke deftly dropped it to Kennedy while avoiding Karlsson, and Kennedy's wrist shot tucked right under the crossbar to beat Anderson on Pittsburgh's 23rd shot of the game.

The Penguins had done a good job of shutting it down defensively in the third period until they somehow lost Alfredsson on his game-tying goal.

"We had two defensemen on the ice, and we were halfway through a change," Bylsma said. "[Ottawa] had their goaltender pulled, so it was five skaters apiece. They were able to make the drop play, which created a big gap in our group. They had the entry there, and obviously the guy who made the drop had the speed going to the net. It was just a play through our guys."

The Senators' penalty kill had a strong night, perfect on six opportunities, including a 5-on-3 kill for 58 seconds early in the second period and allowing two shots on goal on a Penguins power play at 1:56 of the second overtime.

"The penalty killers, I thought, did a great job of giving us confidence as the game went on," Ottawa coach Paul MacLean said.

Senators center Jason Spezza returned to the lineup more than three months after undergoing back surgery. It was the 10th anniversary of Spezza's first career Stanley Cup Playoff game and he tried to get up to speed right away.

On his first shift, Spezza got in on the forecheck and finished a hit on Penguins defenseman Douglas Murray before knocking down forward Brenden Morrow deep in the Pittsburgh end as the Scotiabank Place crowd chanted his name. But Spezza's endurance appeared to be an issue as he tired quickly and had to keep his shifts short.

"It would have been different for me had it been only three periods, but it's good," Spezza said. "There's no better way than jumping headfirst into the pool. That's definitely what I did tonight."

Spezza's creativity with the puck and vision did create a few chances, and though he expressed some concern about his timing in the faceoff circle, he finished the night 15-for-25.

"I thought Jason was fine tonight," MacLean said. "We didn't expect him to have to play two games on his first night back, but that's the way it went."

The Senators looked a bit jittery to start, giving up several good opportunities in the opening 10 minutes, but Anderson managed to keep the game scoreless by turning aside 12 Penguins shots in the first period.

Spezza helped trigger a change in momentum when he won an offensive-zone faceoff and went hard to the net to draw a penalty on Tanner Glass at 16:33 of the first, and it very nearly resulted in a goal when Karlsson's point shot about a minute later was tipped by Turris to force Vokoun into an awkward save, but Jakob Silfverberg could not get a handle on the rebound.

Turris, who had a strong game going head to head with Sidney Crosby all night, very nearly got Ottawa on the board at 16:11 of the second when he danced around Penguins defenseman Kris Letang on a 1-on-3 to open up space and go in on Vokoun, but his shot went well wide of the far post.

"Well, he didn't get a hat trick," MacLean said in a joking manner, referring to Crosby's performance in Game 2. "So it had to be better than it was in Pittsburgh."

There was so much that was better for the Senators than it was in Pittsburgh, including an unlikely shorthanded goal that might have saved their season.